The future is Saltdean Lido is much more secure after its status was upgraded from Grade II to Grade II* listed.
The lido, which was built in 1937, has been the subject of a local campaign after plans emerged to turn the site into a block of 100 flats.
The upgrading of its listing status also improves the chances that the lido will receive additional funding from English Heritage.
Council leader Mary Mears said: “We are extremely pleased that the Secretary of State has upgraded Saltdean Lido as residents are passionate about their local landmark. The lido is one of only 27 surviving in England and one of only three beside the sea.
“It means grant assistance from either English Heritage or the Heritage Lottery that can be put towards restoration costs may become available.”